I hope Accel 36lbs will do as thats what I have for my conversion. I'll let you know how I get on with them, but it will be a few weeks yet, still have to make the harness and program the MicroSquirt.

One side question on the injectors. I noticed the 30/36lb Accel are 14 Ohm impedence and the higher ones, like the 44lb injectors are 12 Ohm. Does this effect anything or does it even matter??

If not, I'll shoot you a PM Dennis. I take it going 'too' high doesn't effect anything much but gives you a little head room on the duty cycle... ?

37 lb/hr injectors are only good for around 300hp at 80% duty cycle at 43.5 psi. I would assume you will be making more HP than that. You really do not want to go over 80% duty cycle. you can overheat the injector, and it either can stick open, or closed, which is what you do not want. You could bump the fuel pressure to around 60 PSI and inch another 50HP or so out of them.

From my understanding, no effect. Higher ohms results in maybe slightly slower pintle opening, but we're talking microseconds difference here that would be nulled by either the tune, or if you were OCD, adjusting injector dead time.

Try this : Fuel Injector Calculator from WitchHunter Performance

Looks like 36lb is good for 300hp on a turbo engine and 350 on a N/A engine.
Looks like I may have been given the wrong info on size then! I should of got 40lb+

Go for the 44lb

You could get to 350 on those injectors if you up the fuel pressure or go with a rising rate pump. That said, I'd just go with bigger injectors an take the guesswork out of it.

Kyle,

As Tippy said, 12 ohm injectors will not be a problem.

I think I'll take you up on those 44lb injectors, Dennis. PM sent.

You guys are awesome! Thanks for all the help.

Thanks for the link, Gavin.

You can't handle the POWAAA!

44lb should easily meet your goals.

The 12 Ohm vs 14 Ohm measurement will not matter for your system. These are both considered high impedance. There is a slight difference in the total current to drive the injectors but this is easily handled by the MS ECU circuit.

You will have to retune the VE table. You will get close with a scale in your req_fuel value but you will still need to fine tune with the injectors. This is due to the resolution change of the VE table versus the amount of fuel flowed by the injector. The car should easily start and drive on the current map with the scaling change for the new injectors. Before you spend a lot of time adjusting the fuel map you should hit the WOT spots where your car is going lean. Basically, verify that your new injectors are large enough before going further.

You can up the fuel pressure to get more out of the injectors. However, this changes idle quality and affects injector dead time. Basically, it can change other aspects of your tune. As long as you baseline your injectors to the new fuel pressure you can easily retune at the higher fuel pressure.

Carry on...

So I got the 44lb injectors installed and everything seems fine. I started to retune and freshen up the lower table using the Tuner Studio autotune (which does a great job BTW). I did a couple of 'high speed' bumps to touch the upper levels but not really aggressive. I reviewed the log file and noticed the duty cycle jumped up to 88% momentarily at around 150 kPa when I goosed the throttle up to about 5000rpm. WTH?

My fuel req. for the injectors is: 7.3 (3.65msec) [ I just let Tuner Studio do the calculation, based on 2999cc @44lb ]
I have the fuel pressure set to 44.5psi.

Would bumping the Fuel Requirement up help any?

Kyle, the req_fuel calculation does not affect the duty cycle. duty cycle is how long the injectors are open before the next injection event. Its a % of time. If you change req_fuel you will have to adjust the fuel map in the opposite direction to compensate so the overall injection time in milliseconds is the same.

What are your settings for injection type? Alternating, simultaneous, # injections per cycle, etc. These make a difference in duty cycle percentage.

momentary at 88% is fine.

Oh, and you are making more power than you think. :)

[QUOTE=jpnovak;9028641]
What are your settings for injection type? Alternating, simultaneous, # injections per cycle, etc. These make a difference in duty cycle percentage.

Oh, and you are making more power than you think.


I'm beginning to think the HP level might be more than I expected as well. :O

The roads were wet the other night and no way could I do a WOT test in 2nd, the wheel would simply break free. (no LSD) 3rd was a bit scary too and didn't test it. Especially with the higher speed that comes with being in 3rd gear. Of course I don't have the meats like most of you real 930 guys, just skinny little 245's in the back.

http://forums.pelicanparts.com/uploa...1457468123.jpg

My 930 has "skinny little" 245s in the back. RE11s stick like much bigger tires.

Dyno
 

So far everything looks pretty good with the new injectors.

My dyno day is set for April 16th!

Anyone interested locally (Seattle/Tacoma) in joining me and getting there car on the dyno, they're welcome to sign up. We're doing a group day. So far only 3 of us are confirmed. We need 5 more to get the total price down to $60 each. Otherwise is $90 each for less than 8 cars.

Drift Office LLC The Dyno Station

LOCATION:

Drift Office
1535 Auburn Way North
Auburn, WA 98002

TIME: 11am

The rate for a dyno session is 90 dollars. (If we have 7 or LESS people.)
The rate for a dyno session is 60 dollars. (If we have 8 or MORE people.)

They use a DynoJet.

If I am running, I am in.

Hmmm. I might be in for that. Not sure which car, but I'll have at least one to go on the rollers. Mark me as a likely while I check the schedule with my wife.

cant wait to see what kind of power you are making! are you still at .5 bar?

Cool project.